- Iodine deficiency with goiter has historically been widespread in the U.S. (especially in the Great Lakes region). This is why iodine was added to salt.
- Until recently, a lot of our iodine intake was from wheat (~ 25%).
- Unfortunately, flour mills have switched from adding iodine to using bromides instead. Bromides in flour was banned in the U.K. in 1990, and in Canada in 1994, as being toxic, but the FDA still allows its use in the U.S.
- As iodine and bromine (and fluorides) are all related chemically (called halides), they can act as competitive inhibitors to each other.
- Because of this, we are seeing iodine deficiencies from both decreased intake, and from bromine and fluorine making the iodine you do have less effective.
- Iodine intakes (estimated by urine output) dropped by ~ 50% from 1971 to 2001 (see article in Salt Institute).
- The current RDA for iodine is ~ 150 mcg/day. Much of this comes from iodine added to salt. Unfortunately, most of the salt used in food processing does not have iodine, and people are using less salt at home (the stuff that is iodized) because of the misguided medical advice (except in those with heart failure) to avoid salt. People who eat more salt live longer.
- An additional problem is that the addition of large amounts of unfermented soy (e.g., soy milk, soy cheese, soy protein added to food) inactivates an enzyme called “thyroid peroxidase” and can cause “hypothyroidism.” This is less of a problem with fermented soy products like tempeh and tofu.
What are the implications of iodine deficiency coming back?
- An epidemic of thyroid problems. Bromides which may block iodine function are implicated in many thyroid disorders (bromides are reported to be 50x higher in thyroid tissue of thyroid cancer patients). Low iodine can contribute to an increased risk of both an under or over active thyroid.
- A key role that iodine plays is in breast tissue, and breast tissue from women with breast cancer have lower iodine levels than healthy controls. This effect is so marked, that hypothyroid women (who free up more iodine for breast tissue use) actually have lower levels of breast cancer. Women in Japan (who get much more iodine in their diet) have a 2/3 lower risk of breast cancer than women in the U.S.It is probable that low iodine is a significant risk factor for breast cancer. One of the upcoming studies that our foundation is planning after we finish the Natural Treatment for Infertility Study is to add high dose iodine (4-5 Iodoral tablets a day) to the treatment protocol of women with breast cancer.
- Low iodine may increase the risk of heart disease. For a review of this issue, see Hypothesis: Dietary Iodine Intake in the Etiology of Cardiovascular Disease in the Journal of the American College of Nutrition.
- Low iodine may also contribute to fatigue and CFS. A study showed that those with low body temperature and fatigue felt better on Iodine 1,500 mcg a day — even though their temperature did not rise with treatment. It is reasonable for those with chronic fatigue, CFS and fibromyalgia to try added iodine (Iodoral) for 3 months to see if it helps.
The accuracy of iodine testing has not been confirmed to my satisfaction, and I find that it often works best to treat clinically based on your symptoms and then see if it helps. Much as we like to have a piece of paper that gives definitive results (lab and x-ray results), sadly these results are often not reliable (see Lab Testing is NOT Reliable!). I would simply treat without doing testing in those who have:
- Breast cysts, tenderness, or cancer. I consider these markers for iodine deficiency.